Full-duplex self-interference weakening method and full-duplex self-interference weakening system

ABSTRACT

This application provides a full-duplex self-interference weakening method and a full-duplex self-interference weakening system. The full-duplex self-interference weakening method includes: separately receiving, by a first port of a dual-polarized receive antenna and a second port of the dual-polarized receive antenna, a signal sent by a transmit antenna; and adjusting and combining the signal received by the first port of the dual-polarized receive antenna and/or the signal received by the second port of the dual-polarized receive antenna, to weaken interference caused by the transmit antenna to the dual-polarized receive antenna. The full-duplex self-interference weakening method and the full-duplex self-interference weakening system provided in this application resolve a problem that a quantity of antennas and an antenna location are limited in an existing antenna interference cancelation method.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/072,589, filed on Oct. 16, 2020, which is a continuation ofInternational Application No. PCT/CN2019/079415, filed on Mar. 25, 2019.The International Application claims priority to Chinese PatentApplication No. 201810356505.X, filed on Apr. 19, 2018. All of theafore-mentioned patent applications are hereby incorporated by referencein their entireties.

TECHNICAL FIELD

This application relates to the communications field, and in particular,to a full-duplex self-interference weakening method and a full-duplexself-interference weakening system.

BACKGROUND

To alleviate a problem that radio spectrum resources are increasinglyscarce as wireless devices exponentially increase, a co-frequency fullduplex (Co-time Co-frequency Full Duplex, CCFD) technology is usuallyused in the communications field to improve utilization of the radiospectrum resources. Compared with a conventional half duplex (HalfDuplex, HD) mode (for example, a frequency division duplex mode or atime division duplex mode), spectrum utilization nearly doubles in aCCFD mode. A CCFD system usually includes a receiver and a transmitter.Because a receive antenna of the receiver is relatively close to atransmit antenna of the transmitter, the receive antenna receives asignal sent by the transmit antenna. Therefore, the signal sent by thetransmit antenna severely affects normal receiving performed by thereceive antenna. In the CCFD system, interference caused by the transmitantenna to the receive antenna is referred to as self-interference.Self-interference cancelation is a hot research topic for implementing afull-duplex technology.

Many researches have been made on a full-duplex self-interferencecancelation technology in the industry at home and abroad, and theself-interference cancelation technology includes antenna interferencecancelation. In an antenna interference cancelation method, a CCFDsystem includes two transmit antennas and one receive antenna, adistance from one of the two transmit antennas to the receive antenna isd, and a distance from the other one of the two transmit antennas to thereceive antenna is d+nλ/2, where n is an odd number, and λ is awavelength. In this way, there is a latency of half a wavelength whensignals from the two transmit antennas arrive at the receive antenna,that is, interference signals received by the receive antenna from thetwo transmit antennas have a phase difference of n, so that the signalstransmitted from the two transmit antennas are superimposed and canceledout when arriving at the receive antenna. Therefore, self-interferenceis significantly attenuated.

However, the foregoing antenna interference cancelation method requiresthree antennas, and has a relatively high requirement on relativelocations of the three antennas. Therefore, the foregoing antennainterference cancelation method has a problem that a quantity ofantennas and an antenna location are limited.

SUMMARY

Embodiments of this application provide a full-duplex self-interferenceweakening method and a full-duplex self-interference weakening system,to resolve a problem that a quantity of antennas and an antenna locationare limited in an existing antenna interference cancelation method.

According to a first aspect, an embodiment of this application providesa full-duplex self-interference weakening method, applied to afull-duplex self-interference weakening system, where the full-duplexself-interference weakening system may include at least a dual-polarizedreceive antenna and a transmit antenna; and the full-duplexself-interference weakening method includes:

-   -   separately receiving, by a first port of the dual-polarized        receive antenna and a second port of the dual-polarized receive        antenna, a signal sent by the transmit antenna; and    -   adjusting and combining the signal received by the first port of        the dual-polarized receive antenna and/or the signal received by        the second port of the dual-polarized receive antenna, to weaken        interference caused by the transmit antenna to the        dual-polarized receive antenna.

The two ports of the dual-polarized receive antenna in the full-duplexself-interference weakening system simultaneously receive the signalsent by the transmit antenna, at least one of the signals received bythe two ports is adjusted, and the two signals including the adjustedsignal are combined, so that self-interference is weakened. According tothe full-duplex self-interference weakening system in this embodiment ofthis application, a quantity of antennas is reduced, and costs arereduced; in addition, there is no requirement on a spatial locationbetween the transmit antenna and the receive antenna, so that costs ofthe full-duplex system are reduced, and a problem that an antennalocation is limited in the full-duplex system is resolved.

In addition, the transmit antenna and the dual-polarized receive antennain the full-duplex self-interference weakening system to which thisembodiment of this application is applied are omnidirectional antennas,and have relatively large signal coverage.

In a first possible implementation of the first aspect, the first portof the dual-polarized receive antenna has a first polarizationdirection, the second port of the dual-polarized receive antenna has asecond polarization direction, the transmit antenna has a thirdpolarization direction, and the first polarization direction, the secondpolarization direction, and the third polarization direction areorthogonal to each other.

Both the polarization directions of the first port and the second portof the dual-polarized receive antenna are orthogonal to the thirdpolarization direction of the transmit antenna, so that both the firstport and the second port of the dual-polarized receive antenna areisolated from a transmit port of the transmit antenna. In this way,interference signals received by the first port and the second port ofthe dual-polarized receive antenna are weakened, and the weakenedinterference signals received by the first port and the second port areadjusted and combined, to further weaken the interference caused by thetransmit antenna to the dual-polarized receive antenna. In addition, thepolarization directions of the two ports of the dual-polarized receiveantenna are orthogonal to the polarization direction of the transmitantenna, so that a signal having a larger amplitude is determined in thesignals received by the two ports of the dual-polarized receive antenna,and an amplitude of the signal having the larger amplitude is attenuatedand a phase of the signal having the larger amplitude is adjusted; inaddition, the signals are combined after the signal is adjusted.Therefore, the self-interference is weakened. The signal having thelarger amplitude is determined, so that a problem that interference isintroduced because an active component is introduced into thefull-duplex self-interference weakening system to amplify an amplitudeof a signal having a smaller amplitude can be avoided, aself-interference weakening effect is improved, and simplification of anadjustment circuit for adjusting the signals received by the two receiveports of the dual-polarized receive antenna in the full-duplexself-interference weakening system is facilitated, thereby simplifying astructure of the full-duplex self-interference weakening system.

In a second possible implementation of the first aspect, the adjustingand combining the signal received by the first port of thedual-polarized receive antenna and/or the signal received by the secondport of the dual-polarized receive antenna includes:

-   -   adjusting a phase and an amplitude of the signal received by the        first port of the dual-polarized receive antenna, and combining        the adjusted signal with the signal received by the second port        of the dual-polarized receive antenna; or    -   adjusting a phase and an amplitude of the signal received by the        second port of the dual-polarized receive antenna, and combining        the adjusted signal with the signal received by the first port        of the dual-polarized receive antenna; or    -   adjusting phases and amplitudes of the signal received by the        first port of the dual-polarized receive antenna and the signal        received by the second port of the dual-polarized receive        antenna, and combining the adjusted signals.

With reference to the second possible implementation of the firstaspect, in a possible implementation, a phase difference between the twoto-be-combined signals is an odd multiple of 180 degrees, and theamplitudes of the two to-be-combined signals are the same.

Self-interference can be canceled by adjusting the phase differencebetween the to-be-combined signals to the odd multiple of 180 degreesand adjusting the amplitudes of the to-be-combined signals to be thesame.

According to a second aspect, this application provides a full-duplexself-interference weakening system, where the system is configured toperform the method according to any one of the first aspect or thepossible implementations of the first aspect, and has technical effectsthe same as that of the method according to any one of the first aspector the possible implementations of the first aspect. Specifically, thesystem includes a module or a component configured to perform the methodaccording to any one of the first aspect or the possible implementationsof the first aspect.

According to the second aspect, the full-duplex self-interferenceweakening system provided in this embodiment of this applicationincludes a transmit antenna, a dual-polarized receive antenna, a signalprocessor, and a combiner, where

-   -   the transmit antenna sends a signal;    -   a first port of the dual-polarized receive antenna and a second        port of the dual-polarized receive antenna separately receive        the signal sent by the transmit antenna;    -   the signal processor adjusts the signal received by the first        port of the dual-polarized receive antenna and/or the signal        received by the second port of the dual-polarized receive        antenna; and    -   the combiner combines the two signals including the adjusted        signal, to weaken interference caused by the transmit antenna to        the dual-polarized receive antenna.

In a first possible implementation of the second aspect, the first portof the dual-polarized receive antenna has a first polarizationdirection, the second port of the dual-polarized receive antenna has asecond polarization direction, the transmit antenna has a thirdpolarization direction, and the first polarization direction, the secondpolarization direction, and the third polarization direction areorthogonal to each other.

In a second possible implementation of the second aspect,

-   -   the signal processor adjusts a phase and an amplitude of the        signal received by the first port of the dual-polarized receive        antenna, and the combiner combines the adjusted signal with the        signal received by the second port of the dual-polarized receive        antenna; or    -   the signal processor adjusts a phase and an amplitude of the        signal received by the second port of the dual-polarized receive        antenna, and the combiner combines the adjusted signal with the        signal received by the first port of the dual-polarized receive        antenna; or    -   the signal processor adjusts phases and amplitudes of the signal        received by the first port of the dual-polarized receive antenna        and the signal received by the second port of the dual-polarized        receive antenna, and the combiner combines the adjusted signals.

With reference to the second possible implementation of the secondaspect, in a possible implementation, a phase difference between the twoto-be-combined signals is an odd multiple of 180 degrees, and theamplitudes of the two to-be-combined signals are the same.

Based on the implementations according to the foregoing aspects, theimplementations may further be combined in this application to providemore implementations.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a full-duplex self-interference weakening system to whichan embodiment of this application is applicable;

FIG. 2 is a schematic flowchart of a full-duplex self-interferenceweakening method according to Embodiment 1 of this application;

FIG. 3 is a first schematic diagram of a principle of a full-duplexself-interference weakening method according to an embodiment of thisapplication;

FIG. 4 is a second schematic diagram of a principle of a full-duplexself-interference weakening method according to an embodiment of thisapplication;

FIG. 5 is a third schematic diagram of a principle of a full-duplexself-interference weakening method according to an embodiment of thisapplication; and

FIG. 6 is a schematic structural diagram of a full-duplexself-interference weakening system according to Embodiment 2 of thisapplication.

DESCRIPTION OF EMBODIMENTS

The following describes the technical solutions in the embodiments ofthis application with reference to the accompanying drawings in theembodiments of this application.

FIG. 1 shows a full-duplex self-interference weakening system to whichan embodiment of this application is applicable. As shown in FIG. 1 ,the full-duplex self-interference weakening system provided in thisembodiment includes at least a transmit antenna, a dual-polarizedreceive antenna, a signal processor, and a combiner. The transmitantenna sends a signal to the outside through a transmit port 0. Tworeceive ports, for example, a port 1 and a port 2 in FIG. 1 , of thedual-polarized receive antenna simultaneously receive the signal that issent by the transmit antenna through the port 0. In this embodiment ofthis application, the two receive ports separately receive the signal,the signal processor adjusts at least one of the signals received by thetwo receive ports, and the combiner combines the two signals includingthe adjusted signal, so that the two signals received by the receiveantenna cancel each other out, thereby weakening interference caused bythe transmit antenna to the dual-polarized receive antenna.

A full-duplex self-interference weakening method according to theembodiments of this application is described below with reference toFIG. 1 .

FIG. 2 is a schematic flowchart of a full-duplex self-interferenceweakening method according to Embodiment 1 of this application. Themethod may be applied to the full-duplex self-interference weakeningsystem shown in FIG. 1 . As shown in FIG. 2 , the full-duplexself-interference weakening method includes the following steps.

S201: A first port of the dual-polarized receive antenna and a secondport of the dual-polarized receive antenna separately receive a signalsent by the transmit antenna.

For example, the dual-polarized receive antenna is used in thefull-duplex self-interference weakening system in this embodiment ofthis application. The dual-polarized receive antenna has twopolarization directions. As shown in FIG. 1 , the dual-polarized receiveantenna includes the first port (namely, the port 1 in FIG. 1 ) and thesecond port (namely, the port 2 in FIG. 1 ), each of the two portscorresponds to one polarization direction, and the polarizationdirection is a direction of an electric field formed during antennaradiation.

For example, when the transmit antenna in the full-duplexself-interference weakening system sends a signal to the outside, thedual-polarized receive antenna in the same system also receives thesignal. This affects normal signal receiving performed by thedual-polarized receive antenna, and consequently, the transmit antennainterferes with the dual-polarized receive antenna.

In a specific signal receiving process, the two ports of thedual-polarized receive antenna have a same phase center, namely, a phasecenter of the receive antenna. Therefore, phases of signals received bythe two ports are the same. However, because the two ports havedifferent polarization directions, strengths of the signal sent by thetransmit antenna in the different polarization directions may bedifferent. Therefore, amplitudes of the signals received by the twoports may be different. Therefore, the two signals received by the twoports of the dual-polarized receive antenna have the same phase but thedifferent amplitudes.

S202: Adjust and combine the signal received by the first port of thedual-polarized receive antenna and/or the signal received by the secondport of the dual-polarized receive antenna, to weaken the interferencecaused by the transmit antenna to the dual-polarized receive antenna.

For example, the first port and the second port of the dual-polarizedreceive antenna are used to simultaneously receive the signal sent bythe transmit antenna, so that two signals having different amplitudesmay be obtained. Therefore, the two signals can be used to suppress eachother, to weaken the interference caused by the transmit antenna to thedual-polarized receive antenna.

Specifically, to implement mutual suppression, at least one of thesignals received by the first port and the second port may be adjusted.After the adjustment, amplitudes of the two to-be-combined signals arecloser. In addition, it is considered that the signal sent by thetransmit antenna is a sine wave, so that after the adjustment, a phasedifference between the two to-be-combined signals is also closer to 180degrees. In this case, the two to-be-combined signals may be combined toweaken the self-interference.

For example, only the signal received by the first port may be adjusted,or only the signal received by the second port may be adjusted, or boththe signals received by the two ports may be adjusted. After the signalis adjusted, the signals are combined to weaken the self-interference.Correspondingly, when only the signal received by the first port isadjusted, the signal received by the second port and the adjusted signalreceived by the first port are combined. Correspondingly, when only thesignal received by the second port is adjusted, the signal received bythe first port and the adjusted signal received by the second port arecombined. When both the signals received by the first port and thesecond port are adjusted, the adjusted signal received by the first portand the adjusted signal received by the second port are combined.

In the full-duplex self-interference weakening method provided in thisembodiment of this application, the two ports of the dual-polarizedreceive antenna in the full-duplex self-interference weakening systemsimultaneously receive the signal sent by the transmit antenna, at leastone of the signals received by the two ports is adjusted, and signalcombination is performed after the adjustment, so that theself-interference is weakened.

The two ports of the dual-polarized receive antenna in the full-duplexself-interference weakening system simultaneously receive the signalsent by the transmit antenna, at least one of the signals received bythe two ports is adjusted, and the two signals including the adjustedsignal are combined, so that the self-interference is weakened.According to the full-duplex self-interference weakening system in thisembodiment of this application, a quantity of antennas is reduced, andcosts are reduced; in addition, there is no requirement on a spatiallocation between the transmit antenna and the receive antenna, so thatcosts of the full-duplex system are reduced, and a problem that anantenna location is limited in the full-duplex system is resolved.

In addition, the transmit antenna and the dual-polarized receive antennain the full-duplex self-interference weakening system to which thisembodiment of this application is applied are omnidirectional antennas,and have relatively large signal coverage.

Optionally, based on the foregoing embodiment, an embodiment of thisapplication further provides a full-duplex self-interference weakeningmethod. In this embodiment, a signal adjustment manner is described indetail.

In this embodiment of this application, the adjusting the signalreceived by the first port of the dual-polarized receive antenna and/orthe signal received by the second port of the dual-polarized receiveantenna specifically includes, adjusting a phase and an amplitude of thesignal received by the first port of the dual-polarized receive antennaand/or a phase and an amplitude of the signal received by the secondport of the dual-polarized receive antenna.

The adjusting the signal received by the first port of thedual-polarized receive antenna or the signal received by the second portof the dual-polarized receive antenna specifically includes: adjusting aphase and an amplitude of the signal received by the first port of thedual-polarized receive antenna or a phase and an amplitude of the signalreceived by the second port of the dual-polarized receive antenna.Optionally, the amplitude adjustment may be amplitude amplification andamplitude reduction, and the phase adjustment may be a forward phaseshift or a backward phase shift.

The adjusting the signal received by the first port of thedual-polarized receive antenna and the signal received by the secondport of the dual-polarized receive antenna includes at least one of thefollowing:

-   -   adjusting a phase and an amplitude of the signal received by the        first port of the dual-polarized receive antenna, and adjusting        a phase and an amplitude of the signal received by the second        port of the dual-polarized receive antenna; or    -   adjusting a phase and an amplitude of the signal received by the        first port of the dual-polarized receive antenna, and adjusting        a phase of the signal received by the second port of the        dual-polarized receive antenna; or    -   adjusting a phase and an amplitude of the signal received by the        first port of the dual-polarized receive antenna, and adjusting        an amplitude of the signal received by the second port of the        dual-polarized receive antenna; or    -   adjusting a phase of the signal received by the first port of        the dual-polarized receive antenna, and adjusting a phase and an        amplitude of the signal received by the second port of the        dual-polarized receive antenna; or    -   adjusting a phase of the signal received by the first port of        the dual-polarized receive antenna, and adjusting an amplitude        of the signal received by the second port of the dual-polarized        receive antenna; or    -   adjusting an amplitude of the signal received by the first port        of the dual-polarized receive antenna, and adjusting a phase and        an amplitude of the signal received by the second port of the        dual-polarized receive antenna; or    -   adjusting an amplitude of the signal received by the first port        of the dual-polarized receive antenna, and adjusting a phase of        the signal received by the second port of the dual-polarized        receive antenna.

Optionally, the amplitude adjustment may be amplitude amplification of asingle signal, amplitude reduction of a single signal, amplitudeamplification of two signals by different times, amplitude reduction oftwo signals by different times, or amplitude amplification of one of twosignals and amplitude reduction of the other one of the two signals. Thephase adjustment may be a forward phase shift of a single signal, abackward phase shift of a single signal, forward phase shifts of twosignals by different degrees, phase shifts of two signals by differentdegrees, or phase shifts of two signals in different directions.

In this embodiment of this application, the phase and the amplitude ofthe signal received by the first port of the dual-polarized receiveantenna and/or the phase and the amplitude of the signal received by thesecond port of the dual-polarized receive antenna are adjusted, so thatadjusted amplitudes of the two signals are closer, and a phasedifference between the two signals is closer to 180 degrees. In thisway, the self-interference is weakened when the two signals arecombined.

Further, based on the foregoing embodiment, an embodiment of thisapplication further provides a full-duplex self-interference weakeningmethod. In this embodiment, to improve a self-interference weakeningeffect, after the signal received by the first port of thedual-polarized receive antenna and/or the signal received by the secondport of the dual-polarized receive antenna are/is adjusted, the phasedifference between the to-be-combined signals is an odd multiple of 180degrees, and the amplitudes of the to-be-combined signals are the same,so that full-duplex self-interference is canceled.

Specifically, when the phase and the amplitude of the signal received bythe first port of the dual-polarized receive antenna are adjusted, theadjusted signal received by the first port is combined with the signalreceived by the second port, where the phase difference between theadjusted signal received by the first port and the signal received bythe second port is an odd multiple of 180 degrees, and the amplitudes ofthe adjusted signal received by the first port and the signal receivedby the second port are the same.

When the phase and the amplitude of the signal received by the secondport of the dual-polarized receive antenna are adjusted, the adjustedsignal received by the second port is combined with the signal receivedby the first port, where the phase difference between the adjustedsignal received by the second port and the signal received by the firstport is an odd multiple of 180 degrees, and the amplitudes of theadjusted signal received by the second port and the signal received bythe first port are the same.

Specifically, when the signal received by the first port of thedual-polarized receive antenna and the signal received by the secondport of the dual-polarized receive antenna are adjusted, the adjustedsignal received by the first port is combined with the adjusted signalreceived by the second port, where the phase difference between theadjusted signal received by the first port and the adjusted signalreceived by the second port is an odd multiple of 180 degrees, and theamplitudes of the adjusted signal received by the first port and theadjusted signal received by the second port are the same.

In this embodiment of this application, the phase difference between theto-be-combined signals is adjusted to the odd multiple of 180 degreesand the amplitudes of the to-be-combined signals are adjusted to be thesame, so that the two signals cancel each other out after beingcombined, thereby canceling the self-interference.

Further, based on any one of the foregoing embodiments, an embodiment ofthis application further provides a full-duplex self-interferenceweakening method. In this embodiment, the first port of thedual-polarized receive antenna has a first polarization direction, thesecond port of the dual-polarized receive antenna has a secondpolarization direction, the transmit antenna has a third polarizationdirection, and the first polarization direction, the second polarizationdirection, and the third polarization direction are orthogonal to eachother, so that the self-interference weakening effect is furtherimproved.

For example, both the polarization directions of the first port and thesecond port of the dual-polarized receive antenna are orthogonal to thethird polarization direction of the transmit antenna, so that both thefirst port and the second port of the dual-polarized receive antenna areisolated from a transmit port of the transmit antenna. In this way,interference signals received by the first port and the second port ofthe dual-polarized receive antenna are weakened, and in this embodimentof this application, the weakened interference signals received by thefirst port and the second port are adjusted and combined, to furtherweaken the interference caused by the transmit antenna to thedual-polarized receive antenna.

In addition, the polarization directions of the two ports of thedual-polarized receive antenna are orthogonal to the polarizationdirection of the transmit antenna, so that a signal having a largeramplitude is determined in the signals received by the two ports of thedual-polarized receive antenna, and an amplitude of the signal havingthe larger amplitude is attenuated and a phase of the signal having thelarger amplitude is adjusted; in addition, the signals are combinedafter the signal is adjusted. Therefore, the self-interference isweakened. The signal having the larger amplitude is determined, so thata problem that interference is introduced because an active component isintroduced into the full-duplex self-interference weakening system toamplify an amplitude of a signal having a smaller amplitude can beavoided, the self-interference weakening effect is improved, andsimplification of an adjustment circuit for adjusting the signalsreceived by the two receive ports of the dual-polarized receive antennain the full-duplex self-interference weakening system is facilitated,thereby simplifying a structure of the full-duplex self-interferenceweakening system.

An example in which determining of a signal having a larger amplitude insignals received by the two ports of the dual-polarized receive antennais facilitated when the polarization directions of the two ports of thedual-polarized receive antenna are orthogonal to the polarizationdirection of the transmit antenna is used below for description.

In an actual use process of the full-duplex self-interference weakeningsystem, it is assumed that a phase center of the transmit antenna islocated on a Z axis in a spatial rectangular coordinate system, and aphase center of the dual-polarized receive antenna is located on an Xaxis. In this case, a direction vector from the transmit antenna to thedual-polarized receive antenna is denoted as {right arrow over (R)}, and{right arrow over (R)} is a propagation direction of a signal sent bythe transmit antenna.

For example, when the polarization direction of the transmit antenna isspecified as the Z axis, FIG. 3 is a first schematic diagram of aprinciple of a full-duplex self-interference weakening method accordingto an embodiment of this application. As shown in FIG. 3 , a thirdpolarization direction of a transmit antenna is a Z axis in a spatialrectangular coordinate system, a first polarization direction of a firstport of a dual-polarized transmit antenna is an X axis in the spatialrectangular coordinate system, and a second polarization direction of asecond port of the dual-polarized transmit antenna is a Y axis in thespatial rectangular coordinate system. The polarization direction of thefirst port (for example, a port 1 in FIG. 3 ) of the dual-polarizedreceive antenna is along the X axis, and the polarization direction ofthe second port (for example, a port 2 in FIG. 3 ) of the dual-polarizedreceive antenna is along the Y axis.

In this case, an angle between a signal propagation direction {rightarrow over (R)} and the X axis is denoted as θ, and an electric fieldthat is excited by the transmit antenna and that is at thedual-polarized receive antenna is denoted as {right arrow over (E)}.Therefore, there is also an angle θ between the electric field {rightarrow over (E)} and the Z axis. The electric field {right arrow over(E)} may be decomposed into two components: a component {right arrowover (E)}_(x) along the X axis and a component {right arrow over(E)}_(z) along the Z axis.

Because the polarization direction corresponding to the port 2 is alongthe Y axis, the polarization direction of the port 2 is orthogonal toboth the two components {right arrow over (E)}_(x) and {right arrow over(E)}_(z) of the electric field {right arrow over (E)}. Because thepolarization direction corresponding to the port 1 is along the X axis,the polarization direction of the port 1 is orthogonal to the component{right arrow over (E)}_(z) that is of the electric field {right arrowover (E)} and that is along the Z axis, and is parallel to the component{right arrow over (E)}_(x) that is of the electric field {right arrowover (E)} and that is along the X axis. Therefore, a strength of asignal received by the port 1 is greater than a strength of a signalreceived by the port 2. In addition, because phase centers of the twoports coincide, it may be considered that phases of the signals receivedby the two ports are the same.

In this case, the signal received by the port 1 is adjusted, and theadjusted signal is combined with the signal received by the port 2, sothat a self-interference weakening effect can be achieved. Further, thephase and an amplitude of the signal received by the port 1 may beadjusted. Specifically, the amplitude of the signal received by thefirst port is attenuated to be the same as an amplitude of the signalreceived by the port 2, and the phase of the signal received by thefirst port is adjusted to be 180 degrees different from the phase of thesignal received by the port 2. In this case, the adjusted signalreceived by the port 1 is combined with the signal received by the port2, so that a self-interference cancelation effect can be achieved.

For example, when the polarization direction of the transmit antenna isspecified as the X axis, FIG. 4 is a second schematic diagram of aprinciple of a full-duplex self-interference weakening method accordingto an embodiment of this application. As shown in FIG. 4 , a thirdpolarization direction of a transmit antenna is an X axis in a spatialrectangular coordinate system, a first polarization direction of a firstport of a dual-polarized transmit antenna is a Z axis in the spatialrectangular coordinate system, and a second polarization direction of asecond port of the dual-polarized transmit antenna is a Y axis in thespatial rectangular coordinate system. The polarization direction of thefirst port (for example, a port 1 in FIG. 4 ) of the dual-polarizedreceive antenna is along the Z axis, and the polarization direction ofthe second port (for example, a port 2 in FIG. 4 ) of the dual-polarizedreceive antenna is along the Y axis.

In this case, an angle between a signal propagation direction {rightarrow over (R)} and the X axis is denoted as θ, and an electric fieldthat is excited by the transmit antenna and that is at thedual-polarized receive antenna is denoted as {right arrow over (E)}.Therefore, there is also an angle θ between the electric field {rightarrow over (E)} and the Z axis. The electric field {right arrow over(E)} may be decomposed into two components: a component {right arrowover (E)}_(x) along the X axis and a component {right arrow over(E)}_(z) along the Z axis.

Because the polarization direction corresponding to the port 2 is alongthe Y axis, the polarization direction of the port 2 is orthogonal toboth the two components {right arrow over (E)}_(x) and {right arrow over(E)}_(z) of the electric field {right arrow over (E)}. Because thepolarization direction corresponding to the port 1 is along the Z axis,the polarization direction of the port 1 is parallel to the component{right arrow over (E)}_(z) that is of the electric field {right arrowover (E)} and that is along the Z axis, and is orthogonal to thecomponent {right arrow over (E)}_(x) that is of the electric field{right arrow over (E)} and that is along the X axis. Therefore, astrength of a signal received by the port 1 is greater than a strengthof a signal received by the port 2. In addition, because phase centersof the two ports coincide, it may be considered that phases of thesignals received by the two ports are the same.

In this case, the signal received by the port 1 is adjusted, and theadjusted signal is combined with the signal received by the port 2, sothat a self-interference weakening effect can be achieved. Further, thephase and an amplitude of the signal received by the port 1 may beadjusted. Specifically, the amplitude of the signal received by thefirst port is attenuated to be the same as an amplitude of the signalreceived by the port 2, and the phase of the signal received by thefirst port is adjusted to be 180 degrees different from the phase of thesignal received by the port 2. In this case, the adjusted signalreceived by the first port is combined with the signal received by thesecond port, so that a self-interference cancelation effect can beachieved.

For example, when the polarization direction of the transmit antenna isspecified as a Y axis, FIG. 5 is a third schematic diagram of aprinciple of a full-duplex self-interference weakening method accordingto an embodiment of this application. For example, as shown in FIG. 5 ,a third polarization direction of a transmit antenna is a Y axis in aspatial rectangular coordinate system, a first polarization direction ofa first port of a dual-polarized transmit antenna is an X axis in thespatial rectangular coordinate system, and a second polarizationdirection of a second port of the dual-polarized transmit antenna is a Zaxis in the spatial rectangular coordinate system. The polarizationdirection of the first port (for example, a port 1 in FIG. 5 ) of thedual-polarized receive antenna is along the X axis, and the polarizationdirection of the second port (for example, a port 2 in FIG. 5 ) of thedual-polarized receive antenna is along the Z axis.

An electric field that is excited by the transmit antenna and that is atthe dual-polarized receive antenna is denoted as {right arrow over (E)}.In this case, a direction of the electric field {right arrow over (E)}is the same as that of the Y axis.

Because the polarization direction corresponding to the port 1 is alongthe Z axis, the polarization direction of the port 1 is orthogonal tothe electric field {right arrow over (E)}. Because the polarizationdirection corresponding to the port 2 is along the X axis, thepolarization direction of the port 2 is also orthogonal to the electricfield {right arrow over (E)}. Therefore, it may be considered that astrength of a signal received by the port 1 is basically the same as astrength of a signal received by the port 2. In addition, because phasecenters of the two ports coincide, it may be considered that phases ofthe signals received by the two ports are the same.

In this case, an amplitude of the signal received by the port 1 or theport 2 is adjusted, and the adjusted signal is combined with the signalthat is not adjusted, so that a self-interference weakening effect canbe achieved. Further, the phase of the signal received by the port 1 orthe port 2 may be adjusted. For example, the phase of the signalreceived by the port 1 is adjusted to be 180 degrees different from thephase of the signal received by the port 2. In this case, the adjustedsignal is combined with the signal received by the port 2, so that aself-interference cancelation effect can be achieved.

In the foregoing embodiments, in the full-duplex self-interferenceweakening system, the polarization direction of the transmit antenna andthe two polarization directions of the dual-polarized receive antennaare orthogonal to each other, and the strengths of the signals receivedby the two receive ports of the dual-polarized receive antenna may bedetermined based on the polarization direction of the transmit antenna;in addition, an attenuator is used to attenuate an amplitude of a signalhaving a higher strength, so that a problem that interference isintroduced because an active component is introduced into thefull-duplex self-interference weakening system to amplify an amplitudeof a signal having a smaller strength can be avoided, and simplificationof an adjustment circuit for adjusting the signals received by the tworeceive ports of the dual-polarized receive antenna in the full-duplexself-interference weakening system is facilitated, thereby simplifying astructure of the full-duplex self-interference weakening system.

Another aspect of the embodiments of this application further provides afull-duplex self-interference weakening system. As shown in FIG. 1 , thefull-duplex self-interference weakening system includes a transmitantenna, a dual-polarized receive antenna, a signal processor, and acombiner, where

-   -   the transmit antenna sends a signal;    -   a first port of the dual-polarized receive antenna and a second        port of the dual-polarized receive antenna separately receive        the signal sent by the transmit antenna;    -   the signal processor adjusts the signal received by the first        port of the dual-polarized receive antenna and/or the signal        received by the second port of the dual-polarized receive        antenna, and    -   the combiner combines the two signals including the adjusted        signal, to weaken interference caused by the transmit antenna to        the dual-polarized receive antenna.

Optionally, the first port of the dual-polarized receive antenna has afirst polarization direction, the second port of the dual-polarizedreceive antenna has a second polarization direction, the transmitantenna has a third polarization direction, and the first polarizationdirection, the second polarization direction, and the third polarizationdirection are orthogonal to each other.

Optionally, the signal processor is specifically configured to adjust aphase and an amplitude of the signal received by the first port of thedual-polarized receive antenna and/or a phase and an amplitude of thesignal received by the second port of the dual-polarized receiveantenna.

For example, FIG. 1 shows a case in which the signal processor isconfigured to adjust a signal received by the first port of thedual-polarized receive antenna.

Optionally, the signal processor may include an amplitude adjuster and aphase adjuster.

Optionally, a phase difference between the to-be-combined signals is anodd multiple of 180 degrees, and the amplitudes of the to-be-combinedsignals are the same.

For example, based on the embodiment shown in FIG. 1 , FIG. 6 is aschematic structural diagram of a full-duplex self-interferenceweakening system according to Embodiment 2 of this application. As shownin FIG. 6 , the full-duplex self-interference weakening system includesa transmit link, a receive link, and a self-interference cancelationcircuit. The transmit link includes a digital-to-analog converter, anup-converter, a power amplifier, and a transmit antenna. A to-be-sentbaseband digital signal Tb is first input into the digital-to-analogconverter, and then sent sequentially through the up-converter, thepower amplifier, and the transmit antenna. The receive link includes adual-polarized receive antenna, a signal processor, a combiner 1, acombiner 2, a low noise amplifier, a down-converter, ananalog-to-digital converter, and a combiner 3. A signal received by thedual-polarized receive antenna in the receive link sequentially passesthrough the signal processor, the combiner 1, the low noise amplifier,the down-converter, and the analog-to-digital converter to complete asignal receiving process, so as to obtain a baseband digital signal Rbon which self-interference is weakened. The self-interferencecancelation circuit includes an antenna self-interference canceler, ananalog self-interference canceler, and a digital self-interferencecanceler. The antenna self-interference canceler includes the transmitantenna in the transmit link, and the dual-polarized receive antenna,the signal processor, and the combiner 1 in the receive link. The analogself-interference canceler receives a signal output by the poweramplifier, and provides a signal obtained after analog self-interferencecancelation to the combiner 2. The digital self-interference cancelerreceives a baseband digital signal, and provides a signal obtained afterdigital self-interference cancelation to the combiner 3.

Specifically, a working process of the full-duplex self-interferenceweakening system is as follows: The transmit link receives a to-be-sentbaseband digital signal Tb, and the digital-to-analog converter convertsthe baseband digital signal Tb into a baseband analog signal. Afterpassing through the up-converter and the power amplifier, the basebandanalog signal is converted into a to-be-transmitted radio frequencysignal TX, and TX is transmitted through the transmit antenna. When thetransmit antenna sends the radio frequency signal TX, the dual-polarizedreceive antenna receives TX, a first port of the dual-polarized receiveantenna receives a first signal R1, and a second port of thedual-polarized receive antenna receives a second signal R2. After thefirst signal R1 and the second signal R2 pass through the signalprocessor and the combiner 1, a radio frequency signal RX on whichantenna self-interference is canceled is obtained.

The analog self-interference canceler obtains, based on the radiofrequency signal TX, a signal Ra approximate to the radio frequencysignal RX, and the combiner 2 subtracts Ra from RX, to cancel analogself-interference.

After the analog self-interference cancelation, the radio frequencysignal RX is converted into a signal Rc through the low noise amplifier,the down-converter, and the analog-to-digital converter. The digitalself-interference canceler obtains, based on the baseband digital signalTb, a signal Rd approximate to the signal Rc, and then the combiner 3subtracts Rd from Rc, to cancel digital self-interference.

In the several embodiments provided in this application, it should beunderstood that the disclosed system, apparatus, and method may beimplemented in other manners. For example, the described apparatusembodiment is merely an example. For example, the unit division ismerely logical function division and may be other division manners inactual implementations. For example, a plurality of units or componentsmay be combined or integrated into another system, or some features maybe ignored or not performed. In addition, the displayed or discussedmutual couplings or direct couplings or communication connections may beimplemented through some interfaces. The indirect couplings orcommunication connections between the apparatuses or units may beimplemented in electronic, mechanical, or other forms.

The units described as separate parts may or may not be physicallyseparate, and parts displayed as units may or may not be physical units,may be located in one position, or may be distributed on a plurality ofnetwork units. Some or all of the units may be selected based on actualrequirements to achieve the objectives of the solutions of theembodiments. The foregoing descriptions are merely specificimplementations of this application. Any variation or replacementreadily figured out by a person skilled in the art based on the specificimplementations provided in this application shall fall within theprotection scope of this application.

In the specification, the claims, and the accompanying drawings of thepresent invention, the terms “first”, “second”, “third”, “fourth”, andthe like are intended to distinguish between similar objects but do notnecessarily indicate a specific order or sequence. It should beunderstood that the data termed in such a way are interchangeable inproper circumstances, so that the embodiments described herein can beimplemented in other orders than the order illustrated or describedherein. Moreover, the terms “include”, “contain” and any other variantsmean to cover non-exclusive inclusion, for example, a process, method,system, product, or device that includes a list of steps or units is notnecessarily limited to those steps or units, but may include other stepsor units not expressly listed or inherent to the process, method,product, or device.

All or some of the foregoing embodiments may be implemented by usingsoftware, hardware, firmware, or any combination thereof. When softwareis used to implement the embodiments, the foregoing embodiments may beimplemented completely or partially in a form of a computer programproduct. The computer program product includes one or more computerinstructions. When the computer program instructions are loaded orexecuted on the computer, the procedures or functions according to theembodiments of this application are all or partially generated. Thecomputer may be a general-purpose computer, a special-purpose computer,a computer network, or other programmable apparatuses. The computerinstructions may be stored in a computer-readable storage medium or maybe transmitted from a computer-readable storage medium to anothercomputer-readable storage medium. For example, the computer instructionsmay be transmitted from a website, computer, server, or data center toanother website, computer, server, or data center in a wired (forexample, a coaxial cable, an optical fiber, or a digital subscriber line(DSL)) or wireless (for example, infrared, radio, or microwave) manner.The computer-readable storage medium may be any usable medium accessibleby a computer, or a data storage device, such as a server or a datacenter, integrating one or more usable media. The usable medium may be amagnetic medium (for example, a floppy disk, a hard disk, or a magnetictape), an optical medium (for example, a DVD), or a semiconductormedium. The semiconductor medium may be a solid-state drive (solid statedrive, SSD).

A person of ordinary skill in the art may be aware that, in combinationwith the examples described in the embodiments disclosed in thisspecification, units and algorithm steps may be implemented byelectronic hardware or a combination of computer software and electronichardware. Whether the functions are performed by hardware or softwaredepends on particular applications and design constraint conditions ofthe technical solutions. A person skilled in the art may implement thedescribed functions by using a different method for each specificapplication.

A person skilled in the art may clearly understand that, for the purposeof convenient and brief description, for a detailed working process ofthe foregoing system, apparatus, and unit, refer to a correspondingprocess in the foregoing method embodiments, and details are notdescribed herein again.

What is claimed is:
 1. A program product which makes a computer toperform a full-duplex self-interference weakening operation, theoperation comprising: separately receiving, by a first port of adual-polarized receive antenna and a second port of the dual-polarizedreceive antenna, a signal sent by a transmit antenna; and adjusting andcombining at least one of the signal received by the first port of thedual-polarized receive antenna or the signal received by the second portof the dual-polarized receive antenna, to weaken interference caused bythe transmit antenna to the dual-polarized receive antenna.
 2. Theprogram product according to claim 1, wherein the first port of thedual-polarized receive antenna has a first polarization direction, thesecond port of the dual-polarized receive antenna has a secondpolarization direction, the transmit antenna has a third polarizationdirection, and the first polarization direction, the second polarizationdirection, and the third polarization direction are orthogonal to eachother.
 3. The program product according to claim 1, wherein theadjusting and combining at least one of the signal received by the firstport of the dual-polarized receive antenna or the signal received by thesecond port of the dual-polarized receive antenna comprises: adjusting aphase and an amplitude of the signal received by the first port of thedual-polarized receive antenna, and combining the adjusted signal withthe signal received by the second port of the dual-polarized receiveantenna; or adjusting a phase and an amplitude of the signal received bythe second port of the dual-polarized receive antenna, and combining theadjusted signal with the signal received by the first port of thedual-polarized receive antenna; or adjusting phases and amplitudes ofthe signal received by the first port of the dual-polarized receiveantenna and the signal received by the second port of the dual-polarizedreceive antenna, and combining the adjusted signals.
 4. The programproduct according to claim 3, wherein a phase difference between twoto-be-combined signals is an odd multiple of 180 degrees.
 5. The programproduct according to claim 3, wherein the amplitudes of the twoto-be-combined signals are the same.
 6. A non-transitorycomputer-readable medium storing a program, wherein the program, whenexecuted, cause a computer to perform a full-duplex self-interferenceweakening operation, the operation comprising: separately receiving, bya first port of a dual-polarized receive antenna and a second port ofthe dual-polarized receive antenna, a signal sent by a transmit antenna;and adjusting and combining at least one of the signal received by thefirst port of the dual-polarized receive antenna or the signal receivedby the second port of the dual-polarized receive antenna, to weakeninterference caused by the transmit antenna to the dual-polarizedreceive antenna.
 7. The computer-readable recording medium according toclaim 6, wherein the first port of the dual-polarized receive antennahas a first polarization direction, the second port of thedual-polarized receive antenna has a second polarization direction, thetransmit antenna has a third polarization direction, and the firstpolarization direction, the second polarization direction, and the thirdpolarization direction are orthogonal to each other.
 8. Thecomputer-readable recording medium according to claim 6, wherein theadjusting and combining at least one of the signal received by the firstport of the dual-polarized receive antenna or the signal received by thesecond port of the dual-polarized receive antenna comprises: adjusting aphase and an amplitude of the signal received by the first port of thedual-polarized receive antenna, and combining the adjusted signal withthe signal received by the second port of the dual-polarized receiveantenna; or adjusting a phase and an amplitude of the signal received bythe second port of the dual-polarized receive antenna, and combining theadjusted signal with the signal received by the first port of thedual-polarized receive antenna; or adjusting phases and amplitudes ofthe signal received by the first port of the dual-polarized receiveantenna and the signal received by the second port of the dual-polarizedreceive antenna, and combining the adjusted signals.
 9. Thecomputer-readable recording medium according to claim 8, wherein a phasedifference between two to-be-combined signals is an odd multiple of 180degrees.
 10. The computer-readable recording medium according to claim8, wherein the amplitudes of the two to-be-combined signals are thesame.